More details have been released about the explosion at a GM Tech Center battery lab yesterday that left one person hospitalized with chemical burns and a possible concussion. In a statement, GM said that while an “experimental battery” was undergoing “extreme testing”, gases were released from the battery cells. Something in the lab then ignited the gases and the subsequent explosion was severe enough to cause structural damage, blowing out windows and forcing open fortified doors. The battery itself was left intact. The Detroit News, according to an unnamed source, reports that prototype lithium-ion battery was made by A123, and that explosion happened during “intensive tests designed to make it fail”. The Warren, Michigan fire commissioner said that the lab was designed with safety in mind so damage was confined to the one laboratory. Though some of the 80 workers in the building were sent home for the day after the explosion, others continued to work. The 63,000 sq ft Global Battery Systems Lab has 176 test cells as well as 49 thermal chambers, where GM tests both production and prototype batteries. A HAZMAT team was dispatched to the facility, as were OSHA and MIOSHA inspectors, because of the injuries.

GM stressed that the incident was not related to the Chevrolet Volt or any other production vehicle. Since the electric version of the Chevy Spark won’t go into production until next year, the battery involved in the explosion might be a developmental version of the batteries A123 will be supplying for that project. It also might be a completely experimental prototype.